Expanded steel load-bearing member



Jan. 15, 1929.

H. M. GERSMAN EXPANDED STEEL LOAD BEARING MEMBER w/Qm.

Filed Feb. 1925 Jan. 15, 1929.

H. M. GERSMAN EXPANDED STEEL LOAD BEARING MEMBER Filed Feb. l

Jan. 15, 1929. 1,699,140

H. M. GERSMAN EXPANDED STEEL LOAD BEARING MEMBER Filed Feb. 9 1925 5 Sheets-She =11 x I N l 2% Q I Q 1 :H! g I Q Inc's/270w aruqqfi-demman Jan. 15, 1929.

H. M. GERSMAN EXPANDED STEEL LOAD BEARING MEMBER rneys 5 Sheets-Sheet 4 Inverfibr HA raey m 64%50740 Filed Feb. 1925 NQ\ NO Nbh !;11II N\ I! Q Q NQQ RN wwg Jan. 15, 1929.

H. M. GERSMAN EXPANDED STEEL LOAD BEARING MEMBER 5 Sheets-Sheet Filed Feb. 9. 1925 I IIHIIIIIIHH" In van 70 Horuay/Yersmah flyornef/S Patented Jan. 15, 1923.

UNITED STATES HARVEY m. GERSMAN, or cnrcaoo, rumors.

EXPANDED STEEL LOAD-BEARING MEMBER.

Application filed February This invention relates to expanded steel load bearing members.

by the degree of expansion and at the same time are of uniform thickness: from end to end.

A still further object is to provide a steel load bearing member which may have a maximum degree of expansion without any weakening oi. the bonds by which the strands are connected to one another or to the chord portions and without any liability of the strands or bonds being torn or fractured at any point under the weight which the. member may be designed to sustain.

In order that those skilled in the art may be fully informed in respect to the manufacture of a load bearing member in which the features of the invention are incorporated I have in the accompanying drawing illustrated not only the load bearing member but also an apparatus and method preferably employed in the production of the same, such apparatus and method forming the subjects of my co-pending applications, Serial Nos. 10.349 and 7,764.

In said drawings:

Figure 1 is a side elevation showing, diagrammatically, apparatus by which the load bearing member may be made.

Figure 2 is a top plan view of the same.

Figure 3 a cross section showing a pre terred form of blank.

Figure l is a plan view of a portion of the b ai r.

l we 5 is across section on the line 5-5 oi. Figure 1., more particularly showing a phase of the slitting operation.

Figure (l a plan view of a portion of the blank conforming to the operation shown in F igure 5.

Figure l' is a cross section on the line 77 of Figure 1, more particularly showing a 'lizirther phase of the slitting operation.

Figure 8 is a plan View of a portion of the a, 1925. Serial m), 7,7 5.

blank conforming to the operation shown in Figure 7. t

Figure 9 is a sectional view of the blank on the line 9-9 of Figure 8. 1

Figure 10 is a cross section on the line 101O of Figure 1, more particularly showing the operation of the compensating rolls by which the bar or strand portions produced by the slitting ot' the blank are caused to be of uniform thicknessthroughout their extent.

Figurevll a plan view of a portion of the blank conforming to the operation shown in Figure 10. a

Figure 12 is a sectional view of the blank on the line 12-12 of Figure 11. The deformation of the strand ortions is shown in this figure on a somew at exaggerated scale 111 order to promote clearness of illustration.

Figure 13 is a cross section on the line 13-13 of Figure 1, more particularly showing the operation of the first expansion roll.

Figure 1a is a plan view of a portion of the pzlgank conforming to the operation of Figure Figure 15 is a sectional view of the blank on the line 15-15 of Figure 14.

Figure 16 is a cross section on the line 1616 of Figure 1, more particularly showing the operation of the second expansion ro Figure 17 is a plan View of a portion of the blank conforming to the operation of Figure 16.

Figure 18 is a sectional view of the on the line 1818 of Figure 17.

Figure 19 is a cross sectional View onthe line 1919 of Figure 1, more particularly showing the operation of the first flattening roll.

Figure 20 is a plan view of a portion of the blank and an adjacent portion of the spreader conforming to the operation of Figure 19.

Figure 21 is a sectional view of the line 21 521 of Figure 20, this view also showing the lower portion of the first flattening roll.

Figure 22 is a cross sectional view on the line 22 .22 of F igure 1, more particularly showing the operation of the second flattening rol i Figure 23 is a plan View of a portion of the blank and an adjacent portion of the spreader conforming to the operation of Figure 22. Y A

Figure 24 is a sectional View onthe line blank and 7 in that the angle ofthe portions which are displaced during the slitting to the shearing edges is at no point greater than a right angle and this characteristic provides for greater facility in the slitting operation than is possible where, as in a blank of regular 1 form, certain portions of the rel) which would be displaced during the slitting operation would lie at an obtuse angle to the shearing edge. In the first stage of the slitting as ellected by the rolls 3 the portion. 2 is moved into a plane normal. to and located centrally of the flanges 1 and parts of the portion 2 (being those parts which provide the intermediatebonds) are similarly displaced while the remaining parts of the portions are held in their original plane and are thu .vvered from the adpiccnt parts of the nation 2. lo the second stage of the slitting as ellccled by the rollers 1; the parts of the portions 2" which during; the li t sta were held in their original plane are moved into the same plane as the portion :2, that is to say a plane normal to and located centrally of the flanges 1, and from' this common plane adjacent parts of both of the portions 2 and are displaced into a common plane parallel to the plane from which the displacement started, the portions so displaced being thus severed from the web along lines parallel and adjacent to the flanges and leaving in the plane from which the displacement started those portions which provide the bonds between the struts and the chords, i. e., the outer lines of bonds, and if, as preferred, the outer lines of Sillb' be sl' r ly distant from the flanges also leav inc; chord portions of the web. In Figures 8 and 9 the strand portions are indicated at 102. the portions which provide the intermediate bonds at 1.03. the portions which provide the bonds of the outer lines at 104 and the chord portions at 105.

The strai'id portions 10- and the intermediate bond iroridingportion 10 are, as above explained, displaced incident to the slitting operation in planes parallel to the planes of the outer bond providing portions 101 and the chord portions 105. In consequence of this displacement the length of the parts between successive portions 104, these parts being two strainl portions 102 and an intermediate bond providing portion 103 located between thrn'i. is greater than the len 'th which these parts had prior to their dis-placeiuent, that is to say prior to the cutting of the outer slits 101.. It follows that as an incident of the slitting open ation there is some stretching of the metal of the displaced portions, This stretching occurs in the parts by which the displaced portions are connected to the outer bond providing portions 101, these parts being;

shown in Figure 0 at 102 and being terminal pa of the and P rti ns 102 which exordered stretching operation, offering as they do less resistance to the stretching" forces than the remaining parts, and would therefore be a source of weakness in the finished beam. I therefore provide for com pensating the stretch of the parts 102* by making all parts of the bond providing portions 103 and the st and portions 102 of equal thickness, this end being best served by attenuating the intermediate bond providing portions 103 and the flat parts of the strand portions 102 prior to the ordered stretching operation whereby said flat parts and their connecting portions 103 a are increased in over-all lengthand are reduced to the same thickness as the connecting parts 102. This operation is accomplished by a pair of unifying or compeneating rolls 5, one acting on the blank from i above and the other from below. The rolls 5 are formed with cooperating transverse corri'igations which are shaped and arranged to deform the displaced portions of the blank into sinuous outline as shown in Figures 11 and 12, the parts 10:" being included in the sinuous curve at any point of which the metal is of the same thickness as at any other point. It is to be noted that the deformation of the strand portions is shown in Figures 11 and 152 on a somewhat exaggerated scale in order to promote clearness of illustration. I

The stretching operation follows the operation of the compensating rolls and is preferably performed in more than one stage, two stages being provided for in the apparatus disclosed. The stretching operation is so performed that the intermediate bond proviciling portions 10? are olfset in paths at right angles to the mean longitudinal plane of the web with the result that the adjacent strand portions at opposite sides of the several slits while remaining in parallel relation are stretched proportionately to the increase in the distance between their ends as measured by their points of connection with the respectivebond providing portions 103 and 101. By proceeding" in this manner the bending of the strands where they join the bond providing portions is along transverse lines and the stretching forces are applied at right angles to those transverse bending lines with the result that there is no possibility of tearing. Various mechanical ELgGRQIGS may be employed tor offsetting the bond providing port 103 1n order to stretch the strand port was 102 As shown in the d {WHIIgS the moon: for

Ward and the r r :1 6 end i arranged to en go the bio:

The teeth 6 in the i stage i stretching operation and are therefore 0 less depth than the t-eth 7 by which the stretching operation is coin fat the completion of the tirot e" 111g operation, as shown 1 i I; i we been etretched "1e compieti on itenei i s Lid portions: it from the sinuoue term 'wi the operation started to 2], partial extent, of the second etm'e of the st tion as shown i f igure 1555, t.

tions hove been etched to 'th may have been deter-1 stretched part which i 1 or we on interme- 1L diate bond providing port L id the st)": od portions thereby connect-ed is iiiepieced into substantial ii-term.

The next step 11?; the e ot t blank into the completed e not sect "=1 This involves operations lnereiy for the production of open work an 1 any sensible stretching or airy ot the para. In the expansion ot the bhi-nh the strand portions are sub ected to o teotoid disphtceinent operation, that IE; to any they are bent outward relatively to one another so rte to extend divergingiy irom the common bond and they are also pushed heck into the central longitudinal plane of the Web= in short, flattened. These operations are :iccoinphshed by mowing the thi es oi: the blank relatively outward end at the some time eppiying pressure to the providing port ons to move them a wp [i111 t} i w nuance nu one i it our does not invoiv I piano of the web. PM: pr. o, bond oviding porti lurch toward the or central longitudino plane of )reod the rate the thiin ree are being a which the bond PL'OViL. portions are pressed beck being propormmo! to the rate at which the flanges ere eed or tightly grenteri further stretching of the istrz iid avoided 1nd at the some time oh iizibiii tearing the strands in the directions or slits 1S avoided. The flut 111i; oi? the t ii roll it) is ilhiet oivergeirt "\vhercby said plate iioin a Width correthe you at the end ot retcini oeer; tron to the Width i d that the Web shed here e an increase .1 :J i. oi sand hangce to: e-

hir increase in the wit th i were ion of the first he ilottening roi :5 e iiiristreted ill F 153;

15 20 z id 2!. twin which .t Wlii be obi3 and ti o rstrz rid portions th at 1); have otijili ii'tti or accommodated them to vet; to the altered posit-ions ot the portion h 1 the iatcrniiy odpicent W elttei'iding from the E siigrht angle to one another ndinzii j opposite strand poritenoing from the portion 103 at d angle to one another. The 1 of the eecmid flattening); roll 9 is netrzited in Figures 22, 23 and 2-1; it Wiii be observed that the per- 1 L03 hoe been forced to :1 position some i. beiow that of Figure 21 the mutual spat-Eng of the thing es 1 has been further increw-1rd and hat the etrzmd portions have T and in like manner adjusted or iiicoinmodrzied themselves to the I'i'iitilfit' eitered positions of the portion 103 and the ff 1. The operation oi? the third ihittened in Figures 26 and. and that of the fourth flattening 1e11, 1'1. inl igrnres 28, 22 and 30. Those operatiotie are s-t inihii to time of the roiie ttzind 9 end invoive further increases in the specing: of the Iiittfi0-7 1 end further flattening oi? :sti' tched (titular-ed portions.

The. fif h and ii mi stage of the expanding operation is 'iertormed by :i pair oi? (:0- operating}; roihi 'iihe epi'emhr 1&5 proii to it some (i in advance (it the "th flattening roi 11 and are the bhink ied form rd from this roil e further increase in the 5pm P9; of: the flanges 1 the spread The who 12 not on the bienh es it par beyond the spr ader. At this time the flanges 1 have been spaced to the .nt c'teterniined upon and the flattening the effected by nearly completed. The ofiice of the rolls 12 is, therefore, to perform the final step of bringing the displaced portions uniformly into the central longitudinal plane of the web and to give a desirable finish to the completed beam. These rolls are therefore shaped and proportioned to act on all parts of the web and are operative to deliver the completed structural member which is shown in Figures 32 and The process described results in a finished product which is a beam expanded from a rolled structural shape in which all of the parts displaced by the expansion lie in the central longitudinal plane of the beam, the structure being integral throughout. In the completed product the strands 102* are of equal thickness throughout their extent, the intermediate bonds 103 are of equal thickness with the strands and the outer bonds 1043 are of somewhat greater thickness than the strands since they are not subject to any stretching and therefore give a greater factor of safety to the structural member.

The above description assumes the production of a lattice truss where the blank has at least three rows of slits but tundamentally the same method can be used for the production of a beam in the form of a lVarren truss. In this case the blank is of regular I cross section and, as shown in Figure 34, has two rows of longitudinal slits 106 and 107, those of one row in breakjoint relation to those of the other row. Between the ends of the slits 106 are portions 108 which provide bonds between the struts and the chord at one side of the beam and between the ends of the slits 107 are portions 109 which provide bonds between the struts and the cord at the opposite side of the beam. The strand portions 110 are delimited by the overlapping portions of the slits 106 and 107 and lie between each pair of adjacent bond providing portions 108 and 100. In the stretching operation each strand portion is bent into substantial V form, the stretching pressure being applied centrally of its length in the same manner in which it is applied to the bond providing portions 103 of the blank used for the lattice truss; The blank at the completion of the stretching operation is shown in Figure 35. The expansion of the blank is carried out in the manner previously described, that is to say the spacing of the flanges is regularly in creased to the extent determined upon and the bent and stretched strand poi-tionsby pressure applied to their apices are simultaneously and at a proportionate rate pressed back into the central longitudinal plane of the beam. The completed structural member is shown in Figures 36 and 37 in which the strands are indicated, at 110 and the bonds at one side at 108* and those atthe other side at 109", the strands being of uniform thick ness throughout and the bonds (which are not stretched) being of somewhat greater thickness than the strands and therefore giving the beam a factor of safety.

Having fully described my invention, I claim 1. An integral load bearing member expanded into truss. form from a rolled shape and having stretched open work and unstretched bonds connecting said open work to the sides of said member.

An integral load bearing member ex panded into truss form from a rolled shape and having stretched open work and unstret-ched bonds connecting said open work to the sides of said member and being of greaterthickness than the parts which provide said open work.

. 3. An integral load bearing member expanded into truss term trom a rolled shape and having stretched strands constituting struts and of uniform thickness from end to end and bonds atthe ends of the strands, the bonds being of greater thickness than the strands.

6. An integral load bearing member expanded. into trussed form from a rolled shape and havin strands constitutin struts and bond portions at the ends of the struts, said member being produced by so stretching the strand portions while the shape is heated and prior to expansion as to bend them from the bond portions along transverse lines and by expanding the shape without further stretching the strand portions, thereby giving the member the qualities specified.

'7. An integral load bearing member expanded into trussed form from a rolled shape and having strands constituting struts and bond portions at the ends of the struts, said member being produced by so stretching the strand portions while the shape is heated and prior to expansion as to bend them from the bond portions along transverse lines, leaving the bond portions unstretched and of original thickness, and by expanding the shape without further stretching' the strand portions, thereby giving the member the qualities specified.

. 8. An integral load bearing member expanded from a rolled shape into the form of a lattice truss and having strands and outer and intermediate bonds therefor, the strands and the intermediate bonds being stretched and the outer bonds being unstretched.

9. An integral load bearing nieniber expanded from a rolled shape into the term of a lattice truss and having strands and outer and intermediate bends therefor, the strands end the intermediate bonds being stretched and the outer bonds being un- 10 stretched and of greater thickness than the strands and the intermediate bonds.

In testimony whereof I aflix my gnziture.

HARVEY M. GERSMAN. 

